User manual
...the world's most energy friendly microcontrollers
2012-04-24 - Giant Gecko Family - d0053_Rev0.96 373
www.energymicro.com
Offset Bit Position
0x3C404
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reset
0
0x17D7
Access
RW
RW
Name
HFIRRLDCTRL
FRINT
Bit Name Reset Access Description
31:17 Reserved
To ensure compatibility with future devices, always write bits to 0. More information in Section 2.1 (p. 3)
16 HFIRRLDCTRL 0 RW Reload Control
This bit allows dynamic reloading of the HFIR register during run time. This bit needs to be programmed during initial configuration
and its value should not be changed during runtime.
Value Mode Description
0 STATIC The HFIR cannot be reloaded dynamically.
1 DYNAMIC The HFIR can be dynamically reloaded during runtime.
15:0 FRINT 0x17D7 RW Frame Interval
The value that the application programs to this field specifies the interval between two consecutive SOFs (FS) or Keep-Alive tokens
(LS). This field contains the number of PHY clocks that constitute the required frame interval. The application can write a value to
this register only after the Port Enable bit of the Host Port Control and Status register (USB_HPRT.PRTENA) has been set. If no
value is programmed, the core calculates the value based on the PHY clock specified in the FS/LS PHY Clock Select field of the
Host Configuration register (USB_HCFG.FSLSPCLKSEL). Do not change the value of this field after the initial configuration. Set to
48000 (1 ms at 48 MHz) for FS and 6000 (1 ms at 6 MHz) for LS.
15.6.30 USB_HFNUM - Host Frame Number/Frame Time Remaining
Register
This register indicates the current frame number. It also indicates the time remaining (in terms of the
number of PHY clocks) in the current frame.
Offset Bit Position
0x3C408
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reset
0x0000
0x3FFF
Access
R
R
Name
FRREM
FRNUM
Bit Name Reset Access Description
31:16 FRREM 0x0000 R Frame Time Remaining
Indicates the amount of time remaining in the current Frame, in terms of PHY clocks. This field decrements on each PHY clock. When
it reaches zero, this field is reloaded with the value in the Frame Interval register and a new SOF is transmitted on the USB.
15:0 FRNUM 0x3FFF R Frame Number
This field increments when a new SOF is transmitted on the USB, and is reset to 0 when it reaches 0x3FFF.